QtQuick Image not changed with ColorOverlay with Qt 5.10 on iOS

With Qt 5.10 on iOS (device not simulator) we see icons using a ColorOverlay which had previously appeared as white showing as black. (see attached images).

The original .png is actually black but we add a ColorOverlay (white) to change the appearance. This is not working on 5.10 iOS. The q,l code looks something like this:

{{ Image {}}

{{    id: thumbnailImage }}{{    }}

{{    anchors.centerIn: }}{{    }}

{{    parent width: 18 }}{{    }}

{{    height: width }}{{    }}

{{    source: thumbnailUrl }}{{    }}

{{    clip: true }}

}

  }}{{{{ ColorOverlay { }}{{    }}

{{    anchors.fill: thumbnailImage }}{{    }}

{{    source: thumbnailImage }}

{{    color: "white" }}

{{ }}}